1. Field of the Invention
This invention concerns new tetramethylaminopiperidine derivatives, and more particularly to products of polyoxyalkylene diamine reacted with alkyl acrylate and further with 2,2',6,6'-tetramethyl-4-aminopiperidine, which are useful as photostabilizers.
2. Description of Related Information
Various synthetic polymers and other materials are light sensitive. When exposed to sunlight or other sources of ultraviolet light, such materials undergo a progressive change in physical properties, typically losing mechanical strength and changing color, resulting in softening, brittleness, discoloration and other undesirable consequences. Photostabilizers have been added to such materials to prevent or diminish their deterioration.
Derivatives of 2,2',6,6'-tetramethyl-4-aminopiperidine (TMAP) have been used as photostabilizers. For example, U.S. Pat. No. 4,526,972 (Speranza et al.) discloses TMAP derivatives made by hydrogenating the product of TMAP reacted with polyoxyalkylene polyamine. U.S. Pat. No. 4,847,380 (Speranza et al.) discloses TMAP derivatives made by reacting polyoxyalkylene diamine or diol with dicarboxylic acid or diisocyanate followed by reaction with TMAP to form TMAP dimer linked to polyoxyalkylene through amide, urea or urethane bonds.
U.S. patent application Ser. No. 07/410,444 (Lin et al.) filed Sep. 20, 1989 discloses reacting alkyl acrylates with a molar excess of polyoxyalkylene polyamine to make polyamidoamines useful as epoxy curing agents, reaction-injection-molding (RIM) chain extenders and other polymer applications.